Package: zim
Version: 0.65-3
The package zim should recommend "gtkspellcheck", rather than "gtkspell".
Zim can use both packages for its built-in spell checker. If both are
installed in Debian 8 Jessie, "gtkspellcheck" will be preferred.
On the other hand, "gtkspell" is no longer available in Debian 9
testing/Stretch.
Therefore, "gtkspellcheck" should be recommended,
From the upstream documentation:
Dependencies: This plugin requires either of two libraries: "gtkspell"
or "gtkspellcheck", if both are installed, the later is used.
http://zim-wiki.org/manual/Plugins/Spell_Checker.html
You can also tell that from the configuration dialog of the Spell
Checker plugin.
--
Hartmut Buhrmester